What's the event loop?

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In computer science, the event loop is a programming construct that waits for and dispatches events or messages in a program. It works by making a request to some internal or external "event provider". When the event loop forms the central control flow construct of a program, as it often does, it may...
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In computer science, the event loop is a programming construct that waits for and dispatches events or messages in a program. It works by making a request to some internal or external "event provider". When the event loop forms the central control flow construct of a program, as it often does, it may be termed the main loop or main event loop read less
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PHP Trainer 5 years

Event loop is a criteria by which you can link a event with calling back a function again. Simpley your time table after eating there is a call back function which makes you sleep. Just for example in node js it is simply same but as it is single threaded that means only a single process can be available...
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Event loop is a criteria by which you can link a event with calling back a function again. Simpley your time table after eating there is a call back function which makes you sleep. Just for example in node js it is simply same but as it is single threaded that means only a single process can be available in ghe program to handle the callback no other function can access the resources. read less
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The Event Loop is a queue of callback functions. When an async function executes, the callback function is pushed into the queue. The JavaScript engine doesn't start processing the event loop until the code after an async function has executed.
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For event loop: /* Within main.js */ var firstFunction=function () { console.log("I'm first!"); }; var secondFunction=function () { setTimeout(firstFunction, 5000); console.log("I'm second!"); }; secondFunction(); /* Results: * => I'm second! * (And 5 seconds later) * => I'm first! ...
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For event loop: /* Within main.js */ var firstFunction=function () { console.log("I'm first!"); }; var secondFunction=function () { setTimeout(firstFunction, 5000); console.log("I'm second!"); }; secondFunction(); /* Results: * => I'm second! * (And 5 seconds later) * => I'm first! */ 1. After secondFunction is placed on the call stack, the setTimeout function is invoked and also placed on the call stack 2. Right after the set Timeout function is executed, something special happens here are the browser places set Timeout callback function (in this case, first Function) into an Event Table. Think of the event table as a registration booth: the call stack tells the event table to register a particular function to be executed only when a specific event happens. And when the event does happen, the event table will simply move the function over to the Event Queue. The beauty of this event queue is that its simply a staging area for functions waiting to be invoked and moved over to the call stack. 3. Executing the set Timeout function moves the callback function (in this case, first Function) to the event table and registers it to with a time delay of 5 seconds. 4. Once first Function has completed its execution, we return to a state where there's nothing in the call stack, the event table doesn't have any events to listen for, and the event queue is empty. read less
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The Event Loop is a queue of callback functions. When an async function executes, the callback function is pushed into the queue. The JavaScript engine doesn't start processing the event loop until the code after an async function has executed.
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